Choose a dormer company: 12 checks before signing
The Dutch dormer market counts 420+ providers, from sole traders to national chains. Quality, warranty and conduct vary widely — Stichting Garantiewoning logged 1,100+ dormer complaints in 2024, mostly about late delivery, poor junctions and mid-project bankruptcies. The 12 checks below filter out 90% of risky companies before you sign.
- Providers in NL (2026)
- ~420 companies
- Complaints 2024
- 1,100+ at Stichting Garantiewoning
- Bankruptcy risk
- ~3% per year
- Reasonable deposit
- Max 20%, not 50%+
- Industry mark
- VEBIDAK + Bouwgarant
- CAR/AVB insurance
- Min. €1.25 m cover
The 12 checks before signing
Work through this list before you sign. Anything that cannot be evidenced by document or certificate doesn't count.
- 1. KvK extract less than 1 month old — check founding date (>3 years ideally), directors, physical address (no PO Box).
- 2. Valid VAT number — verify via VIES or tax authority.
- 3. VEBIDAK membership (roofer trade body) or Bouwgarant participation.
- 4. CAR (Construction All Risks) insurance min. €1.25 m per project — ask for the policy.
- 5. AVB (corporate liability) min. €2.5 m — ask for the policy.
- 6. SBB-recognised training company (indicates investment in craftsmanship).
- 7. References: 3 addresses you can drive past to see recent work.
- 8. Online reviews on independent platforms (Google, Trustpilot, Klantenvertellen) — not just on their own site. Min. 50 reviews, average ≥4.3.
- 9. Quote listing material brands, glass spec (Ug value), frame manufacturer and exact build — no 'standard' without spec.
- 10. Written warranty: minimum 10 years on structure, 10 years on frame, 10 years on HR++ glass, 6 years on roof covering.
- 11. Deposit max 20% (preferably 10%). Statutory ban on >50% before delivery for consumers.
- 12. No pressure tactics: 'sign today and get €1,500 off' is a red flag.
Red flags: stop immediately
Call another company on any of these — no exceptions:
Deposit >30% requested or >50% at start. Refuses to show KvK or policy. 'Construction firm' only operating from another province with no fixed office. Works only with subcontractors, no own tradesmen. Promises install within 2 weeks (normal is 6–12). No written quote, just a 'lump sum'. Cash deposit. Spelling errors in quote, unclear terms, no branding.
Specific 2025-2026: scammers cold-call homeowners 'we'll fit tomorrow because we happen to be in the area'. No serious party works this way.
Industry marks: value and limits
VEBIDAK is the largest trade body. Members pass quality audits, receive technical training and are tied to a disputes committee. Not a 100% guarantee but a higher baseline.
Bouwgarant (from Bouwend Nederland) adds: if the company goes bankrupt the warranty insurer takes over completion (up to €100,000) plus 5 years' completion warranty. Surcharge ~1–2% of project value, usually in the quote.
For roof work specifically: VCA-VOL safety certification and SKG-IKOB for frames add confidence but aren't decisive.
Dispute handling
First step: written complaint (registered post) to the company with 14-day reply window. Keep all correspondence and photos.
Second step (no resolution): disputes committee. For VEBIDAK members: Geschillencommissie Bouw (€127 entry fee); binding ruling in 3–4 months. For Bouwgarant: separate procedure via the guarantee fund.
Third step: civil injunction at court (€314 fee) for urgent disputes, or full proceedings for damages. Budget €1,500–€4,000 in legal costs.
FAQ
- How many quotes should I request?
- Three is the rule of thumb. Two is too few (no comparison), four+ wastes your time. Make them comparable: same size, material, glass spec — otherwise you're comparing apples to oranges.
- Is the cheapest quote always wrong?
- Not automatically, but if one is 25%+ cheaper than the others, ask what differs. Often it's: thinner frame, no drip edge, simpler insulation, no welstand procedure, foreign subcontractor. Compare specifications line by line.
- What if the company goes bust mid-build?
- Without Bouwgarant: you lose the deposit and need to find a new company to finish (often 30–50% more expensive). With Bouwgarant: the insurer arranges completion up to the policy cap. So preferably choose a Bouwgarant participant.
- Can I change things during the build?
- Yes, but document every change in writing (variation order) with price and approval before execution. Verbal arrangements lead to disputes at handover. Budget 8–15% in variations on a typical project.
- How long does the whole process take?
- Quote to signing: 2–4 weeks. Signing to install: 6–12 weeks (frame production). Install itself: 1–3 days. Interior finishing: 2–4 weeks. Total from first contact: 10–20 weeks.